When doing repeated flashing of staff board over USB, using the scriptlet attached, dfu-util often fails with this error (or similar):

dfuIDLE, continuing
DFU mode device DFU version 011a
Device returned transfer size 2048
DfuSe interface name: "Internal Flash  "
Downloading to address = 0x08000000, size = 131072
..............................................Error: Failed to enter idle state on abort

We are still using dfu-util 0.7, which dates back from 2014. There has been a number of upstream fixes since then, including some major refactoring. dfu-util 0.9 seems to work a bit more reliably, and I could reflash staff 16 times before this error occured:

Downloading to address = 0x08000000, size = 131072
^MDownload      [                         ]   0%            0 bytesdfu-util: dfuse_download: libusb_control_transfer returned -4

Let's uprev to dfu-util 0.9 to start with.
 

Deleted: dfu-test 715 bytes

dfu-test 715 bytes View Download